In the first access to https web-page, you may encounter that "connection may be unsafe" in the Yandex web browser. This notification is caused by Safetica certificate in the web-browser, because the Yandex web browser does not support third party certificate.
After first confirmation this notification by button "Go to site (unsafe)" this notification disappears forever. The communication is definitely not unsafe, the communication is safely encrypted.
You can read more information about Yandex and third party certificate here: